by
Lial, Margaret L.; Salzman, Stanley A.; Hestwood, Diana L.

Answer

$\frac{20}{13}$

Work Step by Step

Remember, that the product of a number $a$ and its reciprocal is 1. Therefore, the reciprocal of $a$ must be $\frac{1}{a}$ (which is just $a$ flipped), so that $a\times\frac{1}{a}=1$.
Therefore, the reciprocal of $\frac{13}{20}$ is $\frac{1}{\frac{13}{20}}=1\times\frac{20}{13}=\frac{20}{13}$.
$\frac{13}{20}\times\frac{20}{13}=1$